The present invention relates to a method for strengthening a tooth and root from which the nerve has been removed, and to a dental post which is formed of a relatively soft and plastic polymer, and which is preferably light-transmitting, and can provide centering for the forming of a bracing filler to reinforce internally the walls of pulpless roots while providing for access to the canal in endodontic retreatment procedures.
It is well known art in the dental field to remove an injured nerve, and fill the root apex with gutta percha, preparatory to other reconstructive procedures, including filling the canal with a hard cement material. It is also common, where the coronal part of the tooth is missing or severely damaged, to grind away the diseased remaining upper surface of the tooth so as to provide an appropriate form for a dental prosthesis to be anchored to the tooth via a cast metal anchor extending into the widened root canal. Such dental anchors are generally cemented into the bore hole, or may be held by screw-threads, and in some cases the anchors are provided with textured or undulating lateral surfaces to further assist in securing the anchor to the cement. It has been found, however, that the strength of the repaired tooth, or the security of the dental prosthesis, may be compromised by a severely enlarged canal, with thin remaining walls; in such condition the root may not be sufficiently strong to support a prosthesis, even where the root was firmly anchored in the jaw bone.
Presently, such problems when found in roots with flared and wide canals and with thin, unsupported walls, require further widening and reshaping of the canal to form a continuous straight internal surface, and then filling the space with custom shaped cast metal posts with an extending core foundation above the root for attaching a coronal replacement. However, the difficulties created by the bulky metal post surrounded by thin walled roots are often the cause of split roots requiring the extracting of its fragments and a replacement with costlier implants and prosthetic devices. Another objection and difficulty with metal cast posts, is the unavoidable metal shadow transmitted through the thin root walls and their surrounding soft tissues, which is an impairment to achieving esthetic results, especially in the visible anterior (front) teeth. Further, such individually fashioned cast posts add additional cost, and require a greater number of costly office visits by the patient.
It was also known to use pins, or posts, formed from polymeric plastics, for the formation of dental fixtures, for example, by casting by the `lost wax` process. Such prior pins or posts were not used in the patient's mouth and were generally opaque.